Acute lymphoblastic leukaemia
Leukaemia is a cancer of the blood cells. All blood cells are produced in the bone marrow from stem cells. There are three main types of blood cells:
- bed blood cells: these carry oxygen around the body
- white blood cells: these help to fight off infection
- platelets: these help to stop bleeding and bruising.
There are four main types of leukaemia:
Chronic leukaemias are rare in childhood.
What is acute lymphoblastic leukaemia?
Acute lymphoblastic leukaemia (ALL) is a form of cancer that affects the lymphocyte-producing cells in the bone marrow. Lymphocytes are white blood cells that produce antibodies; they are vital parts of the body’s immune system. There are two main types of lymphocytes: B and T cells.
In ALL there is an accumulation in the bone marrow of immature lymphocyte precursor cells, called blast cells. Eventually the production of normal blood cells is affected by this, resulting in a reduction in the numbers of red cells, normal white cells and platelets in the blood.
ALL is the only form of leukaemia that is more common in children than adults. It is the single most common form of paediatric cancer, accounting for about one-third of all cases in children. About 85% of cases of childhood leukaemia are ALL and it occurs in about 400 children in the UK each year. ALL occurs mostly between the ages of about two and four years. Males are affected more often than females at all ages.
What causes ALL?
There is no single proven cause of childhood ALL but there are a number of suggested causes, some of which are more controversial than others.
Children exposed to higher levels of ionizing radiation before they are born or in early life have been shown to have a high risk of developing childhood leukaemia. One theory is that delayed exposure to a common infection may rarely result in the development of leukaemia.
There is no evidence proving that exposure to high-voltage power lines causes leukaemia.
Symptoms and tests
Many of the symptoms of ALL are due to the fact that the leukaemia cells multiply in the bone marrow and stop the production of healthy blood cells. Common symptoms include:
- fever and infection
- swollen glands
- limb pains.
Tests and investigations
Doctors will need to carry out tests to help decide the best treatment for your child. These tests include:
- blood tests to show if there are any leukaemia cells in the bloodstream and how the other blood cells are affected.
- chest X-ray to show whether any of the lymph glands in the chest are enlarged
- bone marrow aspirate to show what type of ALL your child has
- lumbar puncture to see whether there are any leukaemia cells in the spinal fluid.